


Dead In My Skin

by curseofbunny



Category: Magic Kaito, 名探偵コナン | Detective Conan | Case Closed
Genre: Alpha Kuroba Kaito | Kaitou Kid, Alpha/Beta/Omega Dynamics, Alpha/Omega, Fluff and Smut, M/M, Mating Cycles/In Heat, Omega Kudou Shinichi | Edogawa Conan, Plot What Plot/Porn Without Plot, Possessive Sex, Shinichi is tiny but it's not as bad as you think, They're both 20 here for reasons called author does what they want, Trans Kudou Shinichi | Edogawa Conan, that's enough tags i'm embarrassed, uhhh how the fuck do i tag this
Language: English
Status: Completed
Published: 2020-06-24
Updated: 2020-06-24
Packaged: 2021-03-04 06:55:18
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,751
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24889477
Author URL: https://archiveofourown.org/users/curseofbunny/pseuds/curseofbunny
Summary: Shinichi is tired of people not seeing him as a consenting adult, even though the situation is uniquely annoying.
Relationships: Kudou Shinichi | Edogawa Conan/Kuroba Kaito | Kaitou Kid
Comments: 11
Kudos: 276





	Dead In My Skin

**Author's Note:**

> context: he hits his heat when he's still conan, and even tho he's come clean to ran and friends about his situation, none of them will help him take care of it.
> 
> this has 13 y/o body for conan/shinichi, and both shinichi and kaito are actually 20  
> this is also the first dcmk fic i've published, and it's this! 'm flustered, but basically, don't like don't read, let me know what y'all think, and enjoy?

It had been six months since Shinichi came clean to Ran and the old man about his… condition. Considering this circus had been going on for two and a half years now, his patience was the only miraculous thing about the situation. And, of course, with all that… the tiny body had aged. He grew two inches. And they were worried about him, wanting to help him on his goal, but Shinichi still found himself frustrated.

And he was annoyed that he was frustrated. Two and a half years were far too long. He’d been a 17 year old detective with his whole career ahead of him, now he was a thirteen year old with too much time on his hands and only one goal.

Becoming Kudo Shinichi again.

And, well, one more goal. Which Ran had seemed incredulous about when he brought it up to her.

“No! Of course I won’t help you- you can take heat suppressants, or… or use a heat aid, I don’t care. I won’t help.” She had been stirring dinner on the stove.

Shinichi pinched the bridge of his nose. “Ran. I’m your age. I’m asking for your help with my heat. Just because I’m this size doesn’t mean-”

“It means everything! Shinichi, no.” She turned, brandishing the wooden spoon. “You’re all tiny and… bony and small. It would be creepy to say yes.”

“But you know I hate heat aids! You know I can’t be alone either!” He retaliated, climbing up to sit on the counter. “What am I supposed to do?”

“Well, I don’t know. Why didn’t you have one for the last two years?” She narrows her eyes at him before returning to stirring the stew.

“My body was probably too young. This is about when I got my first, if I remember right.” He looked down at himself. Too small. Too soft. Too useless.

“Shinichi, you’re going to have to figure something out. I won’t do it.”

Ran was beautiful even as she was hurting him.

And he tried asking the others. Hattori had about the same response as her, worried about how things would be between them afterwards, and worried about Shinichi’s size. Hakuba wasn’t interested in sex at all, and the Detective Boys would never be an option if Shinichi could help it. Sonoko wasn't so much a 'no' as a 'not this century', since she wasn't interested in the concept of him, let alone helping him out. Even Haibara wasn’t an option, since she couldn’t help, didn’t want to help, and wouldn’t even be able to do much for him. Shinichi wasn’t keen on asking any of the older detectives, and especially not his neighbor, so… he pressed his hands into his face and took to pacing his room instead.

It was coming soon.

He could feel it.

He was usually better at keeping track of the days.

There’s a knock on his window, and Shinichi opens it on autopilot. Of course, it’s KID post-some kind of heist.

“What do you want?” Shinichi snapped.

“Didn’t we plan on seeing each other, meitantei?” KID croons, tapping the bottom of his chin. Shinichi snaps his teeth at his gloved finger.

“Okay. Why so bitey?”

“Not in the mood.” Shinichi stomps away from the window. KID comes in, for reasons unbeknownst to him.

“What do you want?” He snaps again.

“Well… when I’m in the area, I like to see my favorite detective. And the heist was a bust.” He admitted the second part with a lot less enthusiasm. “Besides, you knew about the visit, didn’t you?”

The anger melts away, but the frustration remains.

“I’m sorry. I’m having a bad night.”

KID moves to sit on his bed, toeing off his shoes. “Well, tell me about it.”

“You’re going to be no help. Just like everyone else.”

“No help-” KID scoffs. “Didn’t I jump out of an airship to catch you once? When am I ever no help?”

“Well, Ran has been my friend since I was little, and she was no help. And… I’m losing hope.” His shoulders slump.

KID frowns. “So, you’re going to tell me what’s wrong, and then you’re going to let me help you, right?”

Shinichi looked to the window, where a cool breeze was still blowing in. His skin was starting to get flushed, and his stomach cramping. The breeze helped.

“My heat is coming.”

There’s a careful nod from KID.

“I… can’t take care of a heat alone. When I was younger, right after my parents moved away, there was a situation. I was in the middle of an intense heat, and someone broke into the house. I couldn’t do anything about most of the minor robbery, but I did manage to incapacitate them, barely. It was humiliating to have to call the precinct, mid-heat, to pick him up. And, not to mention, I hate heat toys. They’re… demeaning. I don’t want a fake dick that’s purple and- and all the extra things. I want a real one. I want to be held. I want to be scented and held and…” He shook his head. “I need help.”

KID nodded again. “Alright.”

Shinichi was getting overheated. He pulled off the jacket he’d thrown on after dinner. “And- I know you don’t want to help me. No one wants to help me, because I’m tiny and ugly and young. Even though I’m a consenting adult, all anyone sees is the bony elbows and chubby cheeks.”

KID had also removed a few layers by this time, leaving him missing his tie, coat, and socks. The costume pieces was folded up on Shinichi’s side table, other than the hat and monocle, which hadn’t been removed yet. “I said yes.”

“I get it. I’m not mad at you for saying no!” Shinichi, oblivious, kept ranting. “I just feel… helpless.”

There’s a pair of gloved fingers on his chin, turning his face towards the other boy, and two lips on his. Shinichi stiffens, before his body melts.

How long had it been since he’d been kissed? There had been that case, with the college student who kissed him before throwing him into a wall. Ayumi or Ran kissing him on the cheeks. Haibara kissing his hand once, to tease him. And then…

Not since he’d still been ‘Kudo Shinichi’.

He’d missed it.

KID nipped his bottom lip, letting his tongue slip into Shinichi’s mouth as the boy gasped. He was shivering now, and KID pulled him forwards to stand between the thief’s thighs.

As they kiss, Shinichi can feel his mind going blank as oxygen slowly runs out. Maybe part of it is the hands running over his skin, under his shirt, pulling at it and pulling it up and up until the kiss suddenly ends to remove the shirt completely.

Shinichi took a second to breathe. When had his hands started resting on KID’s thighs? When had…

He looks up, still panting.

KID hooks a finger in the top of his pajama pants. “Was wondering how I could shut you up.”

“Hah?”

“Meitantei, for someone so great and smart, you’re bad at listening to me sometimes.” KID pulls the pants down so that the crumple around Shinichi’s feet. “I said yes.”

“Yes?”

“Yes. That I’d help you.”

Shinichi swallows, trying not to think about the fact that half the liquid going down his throat was KID’s. The thought, despite him not wanting to think about it, sends a gush of slick downwards, and he scrunches his nose up at the dizzying sensation.

“Why… aren’t you worried? I’m small. And… unattractive.”

“No, your body is small. Your intellect is attractive. And,” KID removes his hat and monocle, setting them aside with care. It’s startling how he treats his costume compared to how he shoves and manhandles Shinichi’s clothes. It also sends another wave of slick, which had been sparse before, and was now running down his bare thighs and wetting his underwear. Doubtless, the stench was filling the room. “You said it yourself. You’re a consenting adult. Why would I treat you like a child?”

“Because… everyone else does?”

“I’m not everyone else.”

KID steals another kiss.

Shinichi relaxes this time. This is safe. This is what he had wanted, before. Someone he trusted to help him through his heat. Fuck him, fill him, and hold him. That’s all he needed.

He barely registers crawling up into KID’s lap, barely registers his underwear being ripped and two gloved fingers rubbing down his stomach.

He does register when the fingers circle his clit, the silky fabric making his thighs quiver.

He does register when his first orgasm hits after just a few short seconds of touching him, kissing him, holding him.

He does register the fingers sinking inside him to stretch him.

He does register the third joining.

He does register shivering in anticipation, holding onto KID’s vest as he’s fingerfucked to a second orgasm.

Shinichi is already a wreck when the fingers are removed.

KID kisses his jaw. "May I put it in?"

Shinichi nods blearily.

He'd never had that moment most omegas mentioned, that 'yes, this cock is too big for me, I need all of it' moment. And yet, he shakes as it presses inside, achingly slow, achingly deep. Shinichi wants all of it. He gasps and grabs KID’s shirt tight.

By the time he’s fully seated, his limbs are shaking, but he’s full. For the first time, he feels full on a heat… it’s amazing.

He’s sure his eyes are clouded with lust as he looks up at KID. “You… you didn’t tell me you were an alpha. You’re… too composed, how?”

KID presses a kiss to his cheek before sliding back on the bed a bit so he can get a better angle to press Shinichi’s ass forwards, getting even more of that cock in, grinding it against him. He gasps again, eyes shutting.

“That’s easy, meitantei. I know how to be patient. If I was mean earlier, you wouldn’t let me be mean to you now.”

Shinichi lets out a puff of laughter. It’s funny, but he’s right.

He nods. “You may move.”

KID doesn’t start thrusting, so much as he cups Shinichi’s hips and moves him back and forth. Being treated like a doll is new, considering most of his partners had been smaller than him, or not strong enough to do so. This is new territory.

And it sends sparks through his system. Shinichi lets out a broken moan, squirming in KID's grip. This can’t be this good, it’s too much-

But it is that good. And it’s relentless.

Shinichi gets his hand up to wrap around KID's tie, and pull it down sharply. KID chokes but follows the nonverbal request, pressing his tongue into Shinichi's mouth again and stealing more of his breath away.

There's no concerns in Shinichi's mind except chasing this pleasure. There's no anxiety, no fear. Just… them. Here.

The detective quivers as another gush of slick eases out of him, against the tight seal of KID's huge cock inside his pussy. He'd always thought it was silly when porn mentioned feeling full, but the pressure is starting to build up. And the fluids are sticky on his thighs, smearing all over the white pants.

Oops… KID would have to steal the clothing of his that he kept at the far back of his closet, where not even Ran went.

That thought sent a wave of possessiveness through him.

 _His_ clothes.

 _His_ alpha.

Shinichi bit KID's tongue.

The thief jerks back, rubbing his bottom lip. "Ah… so mean to me, meitantei.

"Shut up." Shinichi yanked on his tie again to get him close enough to bite again.

KID complies by holding Shinichi's ass still and rocking deeper inside of him, allowing the detective to mark him up and draw blood.

It's rough. It's personal. It's just what Shinichi needed.

KID keeps his body close this time, rocking into him harder. Shinichi can feel the knot swelling up, and even through his heat haze, he knows he wants it inside of him. Not for the obvious reasons of his brain screaming 'alpha alpha alpha', but the rest of his brain, where it was reminding him of how full he'd felt with just that cock in him, and how full he'd be, filled up with cum.

He was embarrassed by how much he wanted it.

KID starts to thrust and rut frantically against Shinichi, the knot forcing it's way inside of him and getting larger and harder. He breaks the kiss to gasp for breath, dizzy in it, and KID gets a hand against the back of his head to press his face into KID's neck. It's almost like a hug, except Shinichi is keening and squirming as he's fucked.

And then KID cums inside him.

They both have to sag after that, one of KID's hands resting on the bed to support him, the other idly rubbing the back of Shinichi's head.

It's better than he thought it would be.

His stomach has bulged a bit from the force of the cum inside him, and his head is still swimming. KID is panting for breath, cock still twitching and pumping cum into Shinichi. As full as he is, his body keeps finding more room for the cum that's still coming.

Shinichi can't breathe, but he can think.

And, honestly, he's thinking that he wants more.

Shinichi works on fixing the strangled tie so he can get it off of KID. How the thief fucked him while wearing a tie and vest was beyond him, but the wet fabric was starting to irritate his sensitive thighs, still spread and shaking.

KID finally looks at him again. "Hm?"

"I'm tired of fucking a thief. I want to see you." Shinichi gives up on the tie's knot. Jii-san can fix it later. He shoves it up, skimming over KID's sweaty face.

"I'm not wearing the monocle or the hat- you _can_ see me." The thief protests.

Shinichi continues. He unbuttons the vest and shoves it back, then does the same to the shirt underneath. And then there's the bulletproof vest, with little compartments for knick knacks. KID takes the hint and shrugs them off, leaving him in his pale blue undershirt.

He's already starting to look right again.

"When- when the knot goes down, take your pants off." Shinichi nods. "That's what I want."

"But then I'll be cold!" He whines, but already works on pulling the belt out of his belt loops.

Shinichi swallows as he looks at it. The other boy glances between his face and his belt, then to the small hands.

"Want me to tie you up?"

Shinichi feels a swell of panic and embarrassment. "No."

The boy pouts at him and gets a hand- still gloved, Shinichi had forgotten the gloves- under Shinichi ass to press him forwards and hold him there. Then the boy shifts until he can shove his pants down and kick them off.

Shinichi gasps, feeling even fuller for a few dizzying seconds.

Then it's over. The knot goes down, and it's just two 20 year olds, sitting on Shinichi's bed together.

The much too small bed.

Which Shinichi fully intended on trapping the thief and, if a heatwave hit during the night, waking the other boy up by riding him.

“Hey… Shin-chan?”

Shinichi blinked in surprise.

“Yes, Kaito-nii-chan?” He pauses. The habit of it… His cheeks flush with embarrassment.

And a few other things.

“Heh…” Kaito noses at his cheek to breathe in his scent. It’s a lot calmer now, and Kaito looks relieved. “Thank you for trusting me.”

“Trusting you?” Shinichi raised an eyebrow. “You happened to be in the wrong place at the right time.”

Kaito nuzzles his cheek. “I was at your place, your space. Your face.”

“Like I said, wrong place.” Shinichi shivers. “I wanna get under the covers, come on. Not warm enough.”

He’s so full, cum spilling down his thighs and onto Kaito’s, and sensitive, that even curling up on his chest under the covers is overwhelming. But..

Like all of this, Shinichi can’t stop himself from doing it.

Kaito kisses his forehead.

Shinichi grumbles.

“Do you wanna sleep, hm, Shinichi-chan?”

Shinichi nodded slowly. “My body… it’s tired. But I want more, before this is over, and that’s the end of that discussion.”

“I’m happy to be whatever you need, meitantei.”

“Shut up, Kid.” Shinichi mumbles.

Even as he’s stealing another kiss, eyes drooping shut.


End file.
